Control of the intermixing of InGaAs/InGaAsP quantum well in impurity free vacancy disordering by changing NH3 flow rate during the growth of SiNx capping layer

Abstract

The dependence of impurity free vacancy disordering (IFVD) of InGaAs/InGaAsP QW structure on the characteristics of dielectric capping layer was studied using SiNx film as capping layers. The characteristics of the SiNx capping layer were varied by changing the NH3 flow rate during SiNx deposition by plasma enhanced chemical vapor deposition (PECVD). The degree of quantum well intermixing (QWI) with SiNx capping layer grown at higher NH3 flow rate was larger than that with SiNx film grown at lower NH3 flow rate. This implies that QWI can be easily controlled by simply changing the reactive gas ratio in the growing process of SiNx capping layer. It was also shown that this method to control QWI is better than the method of using two different capping layers such as SiNx film and SiO2 film in order to get spatially selective QWI on the same substrate.